宁夏河东沙区人工林土壤水分时空变化及其与气象因子之间的关系

为充分了解沙区防护林林地土壤水分时空异质性,以宁夏河东沙区典型防护林树种柠条(Caragana korshinskii)、胡杨(Populus euphratica)、刺槐(Robinia pseudocacia)组成的人工林为研究对象,采用时域反射仪监测不同坡度的各个林地土壤水分动态变化,分析了不同林地土壤水分动态变化及其与气象因子之间的关系。结果表明:(1)柠条林地平均土壤含水率随坡度增加而下降。坡度为10°时,全剖面与激变层和活跃层土壤含水率变化差异显著(P<0.05);坡度为16°时,全剖面、激变层、活跃层以及次活跃层之间无明显差异;坡度为24°时,全剖面与激变层和活跃层差异显著(P<0.05),而活跃层与次活跃层差异显著(P<0.05)。(2)生长季不同林地平均土壤含水率由大到小依次为刺槐林地(7.49%±0.92%)、柠条林地(6.72%±1.46%)和胡杨林地(5.78%±0.76%)。不同层次土壤含水率与气象因子具有一定相关性,其中各个林地与降水量和相对湿度均呈显著正相关,与风速均呈显著负相关。(3)6-7月份是土壤水分的补给期,8-10月份是土壤水分的耗损期。6月份刺槐林地与柠条林地、胡杨林地土壤水分存在显著性差异(P<0.05);10月份胡杨林地与柠条林地、刺槐林地土壤水分存在显著性差异(P<0.05)。

Temporal and Spatial Variation of Soil Moisture in Artificial Forests in Hedong Sandy Area and Its Relationship with Meteorological Factors

In order to effectively understand the soil moisture spatial heterogeneity of the artificial forest stand in sandy area,the typical shelterbelt species Caragana korshinskii,Populus euphratica,and Robinia pseudocacia of Ningxia Hedong Sandy Land were selected as research objects,while the time-domain reflectometry was used to the temporal and spatial changes of soil moisture in different forests monitored on different slopes,to explore the dynamic changes of soil moisture in different forests and their relationship with meteorological factors.The results showed that(1)The average soil moisture content of C.korshinskii forests decreased with slope increasing.When the slope was 10°,the variation of soil moisture content between the full profile and the catastrophic layer and the active layer was significantly different(P<0.05);when the slope was 16°,the difference between the full profile,the catastrophic layer,the active layer,and the secondary active layer was not significant;when the slope was 24°,the total profile was significantly different from the catastrophic layer and the active layer(P<0.05),and the active layer and the secondary active layer were significantly different(P<0.05).(2)The average soil water content of different forests in growing season was ranked by R.pseudoacacia forest land(7.49±0.92%),C.korshinskii forest land(6.72±1.46%)and P.euphratica woodland(5.78±0.76%).The soil moisture content of different levels had a certain correlation with meteorological factors,and each forest land had a significant positive correlation with precipitation and relative humidity,and significant negative correlation with wind speed.(3)The temporal variation of soil moisture content could be divided into two periods,i.e.,moisture recharge period(from June to July)and moisture losing period(from August to October).There was a significant difference between the R.pseudoacacia forest and the C.korshinskii forest land in June(P<0.05).There was a significant difference between P.euphratica forest,and C.korshinskii forest and R.pseudoacacia forest in October(P<0.05).